Aerosol-generating device having a porous mass

ABSTRACT

An aerosol-generating device including an aerosol-generating article comprising an aerosol-forming substrate, a support element, an aerosol-cooling element, and a mouthpiece. At least one of the aerosol-cooling element and the filter comprise a porous mass comprising from 20 to 100 wt. % binder and from 0 to 80 wt. % active or inactive particles.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a non-provisional of U.S. Provisional Application No. 62/562,290, filed on Sep. 22, 2017, the entire contents and disclosure of which are hereby incorporated by reference.

FIELD OF THE INVENTION

The present disclosure generally relates to an aerosol-generating device including a porous mass comprising a binder and optionally active or inactive particles. In particular, the present invention relates to an aerosol-generating device comprising a porous mass comprising from 20 to 100 wt. % binder and from 0 to 80 wt. % active or inactive particles.

BACKGROUND OF THE INVENTION

Some smoking articles provide a smoker with an aerosol which is similar to tobacco smoke. Some smoking articles generate an aerosol vapor from an aerosol generating means by heating the aerosol generating means with a fuel source, e.g., tobacco. The tobacco is sufficiently heated or burned to vaporize the nicotine and produce an aerosol stream containing nicotine. The smoking article may have an outer cylinder of fuel with good smoldering characteristics, preferably cut tobacco or reconstituted tobacco, surrounding a metal tube containing tobacco, reconstituted tobacco or other source of nicotine and water vapor.

In other smoking articles, an inhalable aerosol is generated by the transfer of heat from a heat source to a physically separate aerosol-forming substrate or material, which may be located within, around or upstream from the heat source. During consumption of the aerosol-generating article, volatile compounds are released by heat transfer from the heat source and entrained in air drawn through the aerosol-generating article. As the released compounds cool by passing through a cooling element, they condense to form an aerosol that is inhaled by the user.

Synthetic fibers, for example cellulose esters, are widely used in smoke filters for smoking articles due to the ease with which they can be manufactured into filter rods on standard cigarette manufacturing equipment. These synthetic fibers generally comprise cellulose acetate in the form of crimped, continuous fibers or filaments. Filters made of cellulose ester fibers function, in general, by removing a portion of the particulate matter from the smoke which passes through the fibers. The crimping or other physical positioning of the fibers within the filter serves to increase the surface area of the filaments which come in contact with the smoke. However, filters consisting of such fibers alone do not significantly cool the high temperature aerosol stream and often require further components to cool the aerosol.

Conventional cigarettes combust tobacco and generate temperatures that release volatile compounds. Temperatures for burning tobacco can reach above 800° C. and such high temperatures drive off much of the water contained in the smoke evolved from the tobacco. Mainstream smoke produced by conventional cigarettes tends to be perceived by a smoker as having a low temperature because it is relatively dry. An aerosol generated by the heating of an aerosol-forming substrate with or without burning may have higher water content due to the lower temperatures to which the substrate is heated. Despite the lower temperature of aerosol formation, the aerosol stream generated by such systems may have a higher perceived temperature than conventional cigarette smoke. Therefore, the overall length of the aerosol generating article is longer in order to cool the generated aerosol to an acceptable temperature before inhalation.

Therefore, the need exists for an improved aerosol-generating device that enhances cooling efficiency while maintaining desirable smoking characteristics.

SUMMARY OF THE INVENTION

In some aspects, the present disclosure is directed to an aerosol-generating device comprising an aerosol-generating article. The aerosol-generating article may include an aerosol-forming substrate, a support element, an aerosol-cooling element, and a mouthpiece. At least a portion of at least one of the support element, the aerosol cooling element, and the mouthpiece comprises a porous mass comprising from 20 to 100 wt. % binder and from 0 to 80 wt. % active or inactive particles. In some embodiments, each of the support element, the aerosol cooling element, and the mouthpiece comprises the porous mass. In other embodiments only one or combinations of two of the support element, the aerosol cooling element, and the mouthpiece comprise the porous mass. The binder may comprises a very high molecular weight polyethylene, an ultra high molecular weight polyethylene, or combinations thereof. In some embodiments, the binder may be selected from the group including of polyolefins, polyesters, polyamides, polyacrylics, polystrenes, polyvinyls, cellulosics, and combinations thereof. The binder may further comprise polyolefins, polyesters, polyamides, polyacrylics, polystrenes, polyvinyls, cellulosics, or combinations thereof. In some embodiments, the particles are active particles which may be selected from the group including of ion exchange resins, desiccants, silicates, molecular sieves, silica gels, activated alumina, perlite, sepiolite, Fuller's Earth, magnesium silicate, metal oxides, activated carbon, activated charcoals, and combinations thereof. In other embodiments, the porous mass may include inactive particles comprising heat stable materials such as adsorbent carbons. The adsorbent carbons may be selected from the group including porous grade carbons, graphite, low activity carbons, and non-activated carbons. In other embodiments, the inactive particles comprise inorganic solids selected from the group including ceramics, glass, alumina, vermiculite, clays, bentonite, and inert materials. The porous mass may comprise from 30 to 80 wt. % binder and from 20 to 70 wt. % active or inactive particles, from 30 to 70 wt. % binder and from 30 to 70 wt. % active or inactive particles, or from 40 to 70 wt. % binder and from 30 to 60 wt. % active or inactive particles. In other embodiments, the porous mass may comprise from 70 to 100 wt. % binder and from 0 to 30 wt. % active or inactive particles. In some embodiments, the binder may be a very high molecular weight polyethylene and the active particles may be activated carbon. The porous mass may have an encapsulated pressure drop of less than 3.0 mm water/mm length or of less than 1.0 mm water/mm length. The binder may be configured to undergo repeated heat cycles without structural deformation. The binder may be configured to undergo less than a 10% change in pressure drop. The binder may be hydrophobic. The porous mass may be configured to provide a multi-path air flow. In some embodiments, the porous mass comprises 100 wt. % binder. The support and the aerosol-cooling element may be combined into a single unit and the pressure drop may be substantially the same as compared to the support and aerosol-cooling elements as separate units.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be better understood in view of the appended non-limiting figures, in which:

FIG. 1 shows a cross sectional view of an aerosol generating device in accordance with some embodiments of the present invention.

FIG. 2 shows a cross-sectional view of an aerosol-generating article in accordance with some embodiments of the present invention;

FIG. 3 shows a cross-sectional view of the aerosol-generating device comprising a heating element and the aerosol-generating article of FIG. 2, in accordance with some embodiments of the present invention;

FIG. 4 shows a cross-sectional view of the mouthpiece of the aerosol-generating device of FIG. 2, in accordance with some embodiments of the present invention;

FIG. 5 shows another cross-sectional view of the mouthpiece of the aerosol-generating device of FIG. 2, in accordance with some embodiments of the present invention;

FIG. 6 shows still another cross-sectional view of the mouthpiece of the aerosol-generating device of FIG. 2, in accordance with some embodiments of the present invention;

FIG. 7 shows yet another cross-sectional view of the mouthpiece of the aerosol-generating device of FIG. 2, in accordance with some embodiments of the present invention;

FIG. 8 shows yet another cross-sectional view of the mouthpiece of the aerosol-generating device of FIG. 2, in accordance with some embodiments of the present invention; and

FIG. 9 shows a photomicrograph of a section of the porous mass, in accordance with some embodiments of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

I. Introduction

The present disclosure is directed to an aerosol-generating device comprising an aerosol-forming substrate, a support element, an aerosol-cooling element, and a mouthpiece. At least a portion of at least one of the support element, the aerosol-cooling element, and the mouthpiece may comprise a porous mass comprising from 20 to 100 wt. % binder and from 0 to 80 wt. % active or inactive particles. In some aspects, a portion of the support element, the aerosol-cooling element, and the mouthpiece each comprise a porous mass comprising from 20 to 100 wt. % binder and from 0 to 80 wt. % active or inactive particles. The porous mass provides a multi-path air flow that improves temperature reduction for the aerosol-cooling element allowing for a reduction in overall length of the aerosol-generating device.

In some embodiments, the structure of the porous mass provides for minimal encapsulated pressure drop (i.e., loss of pressure while traveling through the porous mass) while maximizing the interaction of the aerosol with the binder and active or inactive particles. The binder helps promote rapid cooling of the aerosol by undergoing a phase change but does so without significant deformation, enabling the heat of fusion to be utilized for heat removal without degrading the performance or structure of the filter. The binder will soften to quickly remove heat and then gradually release that heat as it solidifies in the period between puffs. This design can be enhanced, modified or complemented with an active or inactive material included in the binder to promote selected filtration or to modify the heat adsorption and release profiles.

Advantageously, using a support element, an aerosol-cooling element, and/or a mouthpiece comprising a porous mass comprising from 20 to 100 wt. % binder and from 0 to 80 wt. % active or inactive particles, promotes rapid cooling of the aerosol. Additionally, the pressure drop values of the mouthpiece or aerosol-cooling element are also decreased, leading to improvements in draw while maintaining the desired hardness of the mouthpiece and cooling properties by the support element, aerosol-cooling element, and/or the mouthpiece, even after repeated use. Specifically, the structural properties of the porous mass are well suited to undergo heat of fusion change without significantly changing or deforming the structure. The porous mass performs well at reducing heat but can also provide positive sensory properties simultaneously if desired.

II. Aerosol-Generating Device

Referring to FIGS. 1 to 3, there are shown some embodiments of an aerosol-generating device (these are representative, but not limited to the devices contemplated hereinafter). In some embodiments, the aerosol-generating device may include, but is not limited to, electronic smoking devices, aerosol-generating devices having a combustible source, smokeless smoking devices, etc. Hereinafter, reference will be made to aerosol-generating devices (unless otherwise specified).

FIG. 1 illustrates an aerosol-generating device 1 according to some embodiments of the present invention. The aerosol generating device 1 comprises a smoking material rod 2 and a mouthpiece 3. The mouthpiece 3 may comprise a porous mass comprising from 20 to 100 wt. % binder and from 0 to 80 wt. % active or inactive particles. The mouthpiece 3 is attached to the smoking material rod 2 by a tipping wrapper 4. The smoking material rod 2 comprises an exterior wrapper 5, a co-axially located combustible fuel source 6 and cut smoking material 7 disposed between the fuel source 6 and the wrapper 5.

In operation, the aerosol generating device 1 is lit and burns along the fuel source length producing very little visible sidestream smoke. The visible sidestream smoke produced is derived from the organic components in the smoking article and is most visible at the end of a puff. The substantially non-combustible wrapper chars to produce a frangible, white ash, similar to conventional cigarette ash and which can be tapped off by the smoker, as required. The non-combustible exterior wrapper 5 upon charring also produces a dark burn line which advances along the smoking article as burning progresses. The smoking article burns back along the fuel source 6. As burning occurs an aerosol is produced from the aerosol-generating cut smoking material 7, which aerosol is drawn into the smoker's mouth. Due to the rapid cooling properties of the porous mass, the aerosol is cooled before inhalation.

FIG. 2 illustrates an exemplary aerosol-generating article 10. The aerosol-generating article 10 may comprise four elements arranged in coaxial alignment: an aerosol-forming substrate 20, a support element 30, an aerosol-cooling element 40, and a mouthpiece 50. These four elements are arranged sequentially and may be circumscribed by an outer wrapper 60 to form the aerosol-generating article 10. The support element 30, aerosol-cooling element 40, and mouthpiece 50 may be referred to collectively as a “filter.” The aerosol-generating article 10 has a proximal or mouth end 70, which a user inserts into his or her mouth during use, and a distal end 80 located at the opposite end of the aerosol-generating article 10 to the mouth end 70. It should be understood, however, that the components in the aerosol-generating article need not be arranged in such a fashion, and that there may be other possible configurations. In fact, the components in the aerosol-generating article can be arranged in alternative arrangements that are not co-axial with other components, e.g., an offset arrangement, an overlapping arrangement, combinations thereof, etc. Further, due to the rapid cooling properties of the porous mass, some of these components may be shortened or entirely removed from the aerosol-generating article 10.

In use, air is drawn through the aerosol-generating article 10 by a user from the distal end 80 to the mouth end 70, or the proximal end. The distal end 80 of the aerosol-generating article 10 may also be described as the downstream end of the aerosol-generating article 10 and the mouth end 70 of the aerosol-generating article 10 may also be described as the upstream end of the aerosol-generating article 10. Elements of the aerosol-generating article 10 located between the mouth end 70 and the distal end 80 can be described as being downstream of the mouth end 70 or, alternatively, upstream of the distal end 80, as appropriate.

The aerosol-forming substrate 20 is located at the extreme distal or downstream end of the aerosol-generating article 10. In the embodiments illustrated in FIG. 2, the aerosol-forming substrate 20 may comprise a gathered sheet of crimped homogenized tobacco material circumscribed by a wrapper. The crimped sheet of homogenized tobacco material may comprise an aerosol-former—such as glycerin.

The support element 30 may be located immediately upstream of the aerosol-forming substrate 20 and abuts the aerosol-forming substrate 20. In some aspects, the aerosol-forming substrate 20 may be proximal to the support element 30 but not abutting. In the embodiments shown in FIG. 2, the support element 30 may be a hollow cellulose acetate tube. The support element 30 locates the aerosol-forming substrate 20 at the extreme distal end 80 of the aerosol-generating article 10 so that it can be penetrated by a heating element of an aerosol-generating device. As described further below, the support element 30 acts to prevent the aerosol-forming substrate 20 from being forced upstream within the aerosol-generating article 10 towards the aerosol-cooling element 40 when a heating element of an aerosol-generating device is inserted into the aerosol-forming substrate 20, or as heat is otherwise may be applied to the aerosol-forming substrate 20. In some embodiments, the support element 30 also acts as a spacer to space the aerosol-cooling element 40 of the aerosol-generating article 10 from the aerosol-forming substrate 20. In some embodiments, the support element 30 and the aerosol-cooling element 40 can form a single unit of the aerosol-generating article 10, which may allow the mouthpiece to be lengthened, and/or may allow for the overall total length of the support element 30, the aerosol-cooling element 40, and the mouthpiece 50 to be reduced. For example, this single unit may be formed when the mouthpiece comprises a filter rod comprising a porous mass. In some aspects, when the single unit is formed, the pressure drop is substantially the same as compared to the support element and aerosol-cooling element each as separate units, e.g., within 0.5%.

As shown in FIG. 2, the aerosol-cooling element 40 is located immediately upstream of the support element 30 and abuts the proximal end of support element 30. In other embodiments, the aerosol-cooling element 40 does not abut the proximal end of the support element 30. In use, volatile substances released from the aerosol-forming substrate 20 travel upstream along the aerosol-cooling element 40 towards the mouth end 70 of the aerosol-generating article 10. The volatile substances may cool within the aerosol-cooling element 40 to form an aerosol that is inhaled by the user. The aerosol-cooling element may include a porous mass comprising from 20 to 100 wt. % binder and from 0 to 80 wt. % active or inactive particles, circumscribed by a wrapper 90. The porous mass may define a plurality of channels for air flow that extends along the length of the aerosol-cooling element 40.

The mouthpiece 50 is located immediately upstream of the aerosol-cooling element 40 and abuts the proximal end of the aerosol-cooling element 40. In some embodiments, the mouthpiece may not abut the proximal end of the aerosol-cooling element 40. In some aspects, the aerosol generating device may further comprise another support element between the aerosol-cooling element 40 and the mouthpiece 50. As shown in FIG. 2, the mouthpiece 50 comprises a porous mass comprising from 20 to 100 wt. % binder and from 0 to 80 wt. % active or inactive particles.

To assemble the aerosol-generating article 10, the four elements described above are aligned and tightly wrapped within the outer wrapper 60. In the embodiment illustrated in FIG. 2, the outer wrapper is a conventional cigarette paper.

In some embodiments, a distal end portion of the outer wrapper 60 of the aerosol-generating article 10 is circumscribed by a band of tipping paper (not shown).

The aerosol-generating article 10 illustrated in FIG. 2 is designed to engage with an aerosol-generating device comprising a heating element in order to form an aerosol that is consumed by a user. In use, the heating element of the aerosol-generating device heats the aerosol-forming substrate 20 of the aerosol-generating article 10 to a sufficient temperature to volatilize compounds that are capable of forming an aerosol, which is drawn downstream through the aerosol-generating article 10 and inhaled by the user.

FIG. 3 illustrates a portion of an exemplary aerosol-generating system 100 comprising an aerosol-generating device 110 and an aerosol-generating article 10 according to the embodiment described above and illustrated in FIG. 2.

In one embodiment, the aerosol-generating device 110 comprises a heating element 120. As shown in FIG. 3, the heating element 120 is mounted within an aerosol-generating article receiving chamber of the aerosol-generating device 110. In use, the user inserts the aerosol-generating article 10 into the aerosol-generating article receiving chamber of the aerosol-generating device 110 so that the heating element 120 is directly inserted into the aerosol-forming substrate 20 of the aerosol-generating article 10 as shown in FIG. 3. In the embodiment shown in FIG. 3, the heating element 120 of the aerosol-generating device 110 is a heater blade. Of course, other aerosol-generating device configurations may be employed without deviating from the scope of the present disclosure.

The aerosol-generating device 110 comprises a power supply and electronics (not shown) that allow the heating element 120 to be actuated. Such actuation may be manually operated or may occur automatically in response to a user drawing on an aerosol-generating article 10 inserted into the aerosol-generating article receiving chamber of the aerosol-generating device 110. A plurality of openings are optionally provided in the aerosol-generating device to allow air to flow to the aerosol-generating article 10. FIG. 3 provides one exemplary direction of air flow as illustrated by the arrows. In other aspects, the porous mass in either the aerosol-cooling element, the support, the mouthpiece, or any combination thereof, may provide for multi-path air flow. The structure of the porous mass may include one or more channels for multi-directional air flow. In conventional aerosol-generating devices, air must first pass through the support element which has little to no cooling effect. The air then passes through the aerosol-cooling element, and finally the mouthpiece. Without being bound by theory, it is believed that the porous mass allows for such multi-directional air flow because unlike a crimped fiber which is solely oriented parallel to the air flow, the pores of the porous mass are random. Therefore, the porous mass does not restrict the air flow direction and instead provides a tortuous path, leading to improved cooling. In this way, the porous mass improves temperature reduction for the aerosol-cooling element, the support element, and/or the mouthpiece. Such improved temperature reduction may also allow the aerosol-cooling element, the support, and/or the mouthpiece to be shorter in length when a porous mass is used in one of those elements, as compared to a crimped fiber. These effects are further amplified by the efficiency of the binder and the optional active or inactive ingredient particles. Additionally, the stability of the binder at higher temperatures can allow the filter to function when placed directly against the aerosol generating segment. The support element 40 of the aerosol-generating article 10 resists the penetration force experienced by the aerosol-generating article 10 during insertion of the heating element 120 of the aerosol-generating device 110 into the aerosol-forming substrate 20. As a result, the support element 40 of the aerosol-generating article 10 resists downstream movement of the aerosol-forming substrate within the aerosol-generating article 10 during insertion of the heating element of the aerosol-generating device into the aerosol-forming substrate.

Once the internal heating element 120 is inserted into the aerosol-forming substrate 10 of the aerosol-generating article 10 and actuated, the aerosol-forming substrate 20 of the aerosol-generating article 10 is heated to a temperature of less than 400° C. (or other temperature as discussed herein) by the heating element 120 of the aerosol-generating device 110. At this temperature, volatile compounds are evolved from the aerosol-forming substrate 20 of the aerosol-generating article 10. As a user draws on the mouth end 70 of the aerosol-generating article 10, the volatile compounds evolved from the aerosol-forming substrate 20 are drawn downstream through the aerosol-generating article 10 and condense to form an aerosol that is drawn through the mouthpiece 50 of the aerosol-generating article 10 into the user's mouth.

As the aerosol passes downstream through the aerosol-cooling element 40, the temperature of the aerosol can be reduced due to transfer of thermal energy from the aerosol to the aerosol-cooling element 40. When the aerosol enters the aerosol-cooling element 40, its temperature may be in the order of 60° C. Due to cooling within the aerosol-cooling element 40, the temperature of the aerosol as it exits the aerosol-cooling element may be in the order of 40° C. Thus, a temperature reduction of at least 10° C., e.g., at least 20° C. or at least 30° C., may be achieved.

III. Porous Mass

As described herein, the present disclosure relates to a porous mass used in a smoking device, particularly an aerosol-generating device. Specifically, the porous mass may form at least a portion of the support element, the aerosol-cooling element, the mouthpiece, or some combination of any or all, of the aerosol-generating device.

In the embodiments shown in FIGS. 4 to 8, various arrangements of the mouthpiece having the porous mass are shown and described. These embodiments are illustrative of any combination of conventional materials, e.g., cellulose acetate, and the porous mass in the mouthpiece. It is contemplated that the support element and aerosol element may also include the porous mass in various arrangements, however, these are not shown in FIGS. 4 to 8.

FIGS. 4-8 illustrate various embodiments of the mouthpiece of the aerosol-generating device of FIG. 2, in accordance with embodiments of the present invention. As described with reference to the mouthpiece, the “filter 51” is different than the combination “filter” of the mouthpiece, support, and aerosol-cooling element referenced herein. The mouthpiece 50 includes a filter 51 that may comprise a porous mass comprising from 20 to 100 wt. % binder and from 0 to 80 wt. % active or inactive particles. For example, in FIG. 4, the entire filter 51 of the mouthpiece 50 may comprise the substantially uniform porous mass.

In FIG. 5, the mouthpiece 50 has a filter 51 including two segments. In this embodiment, the porous mass 53 is located adjacent to the mouth end 70 of the mouthpiece 50. Conventional filter materials 52 may be located downstream adjacent to the aerosol-cooling element. It is also contemplated that the porous mass 53 can be located downstream adjacent to the aerosol-cooling element 40. For example, FIG. 6 illustrates an embodiment of the mouthpiece 50 where the conventional filter materials 53 are upstream adjacent to the mouth end 70, and the porous mass 52 is downstream adjacent to the aerosol-cooling element 40.

In FIG. 7, the mouthpiece 50 includes a multi-segmented filter 51 comprising three segments. In this embodiment, conventional filter materials 53 may flank the porous mass 52. For example, one conventional filter material 53 may be provided at a proximal end adjacent to the mouth end 70 and another conventional filter material may be provided downstream proximal to the aerosol-cooling element 40 with the porous mass 52 sandwiched therebetween. Similarly, as shown in FIG. 8, one or more porous masses 52 may flank conventional filter materials 53 in a similar arrangement with one porous mass 52 at a proximal end adjacent to the mouth end 70 and another porous mass 52 may be provided downstream proximal to the aerosol-cooling element 40, and the conventional filter 53 is sandwiched therebetween. In the embodiments illustrated in FIGS. 7 and 8, the filter segments may be any combination of conventional materials and porous mass (so long as at least one of those sections is the porous mass. In some embodiments, the support element and the aerosol-cooling element comprise a porous mass and the mouthpiece may comprise cellulose acetate.

The foregoing embodiments are representative and not limiting. Of course, the inventive filters may have any number of sections, for example, 2, 3, 4, 5, 6, or more sections. Moreover, the sections may be the same as one another or different from one another. For example, the sections may have a stacked arrangement of the filter materials. The filters may have a diameter in the range from 5 to 10 mm and a length from 5 to 100 mm.

In some embodiments, the support element may comprise the porous mass. In other embodiments, the aerosol-cooling element comprises the porous mass. In some embodiments, the mouthpiece comprises the porous mass. In other embodiments, the support element and the aerosol-cooling element comprise the porous mass. In other embodiments, the support element and the mouthpiece comprise the porous mass. In further embodiments, the aerosol cooling element and the mouthpiece comprise the porous mass. In other embodiments, the support element, the aerosol cooling element, and the mouthpiece comprise the porous mass.

The porous mass described herein may be prepared as a filter rod to be used as a filter in an aerosol-generating device. In some embodiments, producing filters and/or filter sections may involve cutting filter rod lengths or filter rods. In some embodiments, producing filter sections may involve cutting filter rod lengths, filter rods, or filters. The filter rod lengths, filter rods, and/or filter sections may have any cross-sectional shape including, but not limited to, circular, substantially circular, ovular, substantially ovular, polygonal (including those with rounded corners), or any hybrid thereof.

In the foregoing embodiments, the conventional materials and porous mass are joined. Joined, as used herein, means that the porous mass is in-line (or in series) with the tobacco column; so, that when the user draws on the heated cigarette, smoke from the tobacco column must pass through (e.g., in series) the porous mass and, most often, through both the porous mass and the conventional filter materials. As shown in FIGS. 5-8, the porous mass and the conventional filter materials are co-axial, juxtaposed (next to but not contacting), abutting, and have equivalent cross-sectional areas (or substantially equivalent cross-sectional areas). But, it is understood that the porous mass and the conventional materials need not be joined in such a fashion, and that there may be other possible configurations. Moreover, while, it is envisioned that porous mass, most often, will be used in a combined or multi-segmented filter configuration, as shown in FIGS. 5-8; the invention is not so limited and the filter may comprise only the porous mass, as discussed above with regard to FIG. 4. Further, while it is envisioned that the porous mass will be juxtaposed to the tobacco column, as shown in FIG. 2, it is not so limited. For example, the porous mass may be separated from the tobacco by a hollow cavity (e.g., a tube or channel).

The conventional filter materials employed may include, hut are not limited to, fibrous tows (e.g., cellulose acetate tow, polyolefin tow, and combinations thereof), paper, void chambers (e.g., formed by rigid elements, such as paper or plastic), baffled void chambers, and combinations thereof. Also included are fibrous tows and papers with active ingredients (adhered thereto or impregnated therein or otherwise incorporated therewith). Such active materials include activated carbon (or charcoal), ion exchange resins, desiccants, or other materials adapted to affect the tobacco smoke. The void chambers may be filled (or partially filled) with active ingredients or materials incorporating the active ingredients. Such active ingredients include activated carbon (or charcoal), ion exchange resins, desiccants, or other materials adapted to affect the tobacco smoke. Additionally, the conventional material may be a porous mass of binder (i.e., binder alone without any active particles). For example, this porous mass without active particles may be made with thermoplastic particles (such as polyolefin powders, including he binder discussed below) that are bonded or molded together into a porous cylindrical shape.

In some embodiments, the porous mass may comprise inactive particles that are heat stable materials. The inactive particles may comprise adsorbent carbons including, but not limited to, porous grade carbons, graphite, low activity carbons, and non-activated carbons. In other embodiments, the inactive particles comprise inorganic solids including, but not limited to, ceramics, glass, alumina, vermiculite, clays, bentonite, and inert materials.

The porous mass comprises active or inactive particles bonded together with binder. For example, FIG. 9 shows a photomicrograph of an embodiment of the porous mass where active particles (e.g., activated carbon particles) 57 are bonded into the porous mass by binder 58. (The active particles and the binder are discussed in greater detail below.) This porous mass is constructed so that it has a minimal encapsulated pressure drop (i.e., loss of pressure while traveling through the porous mass) while maximizing the active particles surface area (i.e., functionality of the active particle is increased by exposing the surface area of those particles). Note: in this embodiment (FIG. 9), binder and active particles are joined at points of contact, the points of contact are randomly distributed throughout the porous mass, and the binder has retained their original physical shape (or substantially retained their original shape, e.g., no more that 10% variation (e.g., shrinkage) in shape from original).

In terms of ranges, the porous mass may comprise from 0 to 80 wt. % active or inactive particles, e.g., from 0.01 to 80 wt. %, from 5 to 75 wt. %, from 10 to 75 wt. %, from 20 to 70 wt. %, from 0 to 30 wt. %, from 30 to 70 wt. %, from 30 to 60 wt. %, or from 40 to 50 wt. %. In some aspects, the particles may be present but the porous mass may comprise less than 80 wt. % active or inactive particles, e.g., less than 70 wt. %, less than 60 wt. %, less than 50 wt. %, less than 40 wt. %, less than 30 wt. %, less than 20 wt. %, less than 10 wt. %, or less than 5 wt. %. The porous mass may comprise from 20 to 100 wt. % binder, e.g., from 70 to 100 wt. %, from 20 to 99.9 wt. %, from 25 to 95 wt. %, from 25 to 90 wt %, from 30 to 70 wt. %, from 30 to 80 wt. %, from 40 to 70 wt. % or from 50 to 60 wt. %. In some embodiments, the porous mass may comprise 100 wt. % binder,

In some embodiments, the porous mass has a void volume in the range of 40-90%. In another embodiment, it has a void volume of 60-90%. In yet another embodiment, it has a void volume of 60-85%. Void volume refers to the free space between the active particles and the binder after the porous mass is formed,

As used herein, the term “encapsulated pressure drop” or “EPD” refers to the static pressure difference between the two ends of a specimen when it is traversed by an air flow under steady conditions when the volume flow is 17.5 ml/sec at the output end when the specimen is completely encapsulated in a measuring device so that no air can pass through the wrapping. EPD has been measured herein under the CORESTA (“Cooperation Centre for Scientific Research Relative to Tobacco”) Recommended Method No. 41, dated June 2007. Higher EPD values translate to the smoker having to draw on a smoking device with greater force. The porous mass optionally has an encapsulated pressure drop (EPD) of less than 3.0 mm of water per mm length of porous mass. In another embodiment, the porous mass has an EPD of less than 1.0 mm of water per mm length of porous mass. And, in yet another embodiment, the porous mass has an EPD of equal to or less than 0.6 mm of water per mm length of porous mass (or no greater than 0.6 mm of water per mm length of porous mass) or equal to or less than 0.5 mm of water per mm length of porous mass (or no greater than 0.5 mm of water per mm length of porous mass). In some embodiments, to obtain the desired EPD, the active particles must have a greater particle size than the binder. In one embodiment, the ratio of binder particle size to active particle size is in the range from 1:1.5 to 4.0.

In some embodiments, the porous mass has a length from 2 to 25 mm, e.g., from 5 to 20 mm or from 15 to 20 mm.

The porous mass may have any physical shape; in one embodiment, it is in the shape of a cylinder.

The active or inactive particles may be any material adapted to enhance smoke flowing thereover and facilitate heat removal or dissipation of heat, e.g., high heat capacity materials. By “adapted to enhance smoke flowing thereover” it is meant that any material that can remove or add components to smoke. The removal may be selective. In tobacco smoke from a cigarette, carbonyls (e.g., formaldehyde, acetaldhyde, acetone, propionaldehyde, crotonaldehyde, butyraldehyde, methyl ethyl ketone, acrolein) and other compounds (e.g., benzene, 1,3 butadiene, and benzo[a]pyrene (or BaPyrene)), for example, may be selectively removed. One example of such a material is activated carbon (or activated charcoal or activated coal). The activated carbon may be low activity (50-75% CCl₄ adsorption) or high activity (75-95% CCl₄ adsorption) or a combination of both. Other examples of such materials include ion exchange resins, desiccants, silicates, molecular sieves, silica gels, activated alumina, perlite, sepiolite, Fuller's Earth, magnesium silicate, metal oxides (e.g., iron oxide), and combinations of the foregoing (including activated carbon). Ion exchange resins include, for example, a polymer with a backbone, such as styrene-divinyl benezene (DVB) copolymer, acrylates, methacrylates, phenol formaldehyde condensates, and epichlorohydrin amine condensates; and a plurality of electrically charged functional groups attached to the polymer backbone. In one embodiment, the active particles are combination of various active particles.

In some embodiments, the active particles have an average particle size from 0.5 to 5000 microns, e.g., from 10 to 1000 microns, or from 200 to 900 microns, or a mixture of particle sizes. In further embodiments, the active particles may be a mixture of various particle sizes having an average particle size from 0.5 to 5000 microns, e.g., from 10 to 1000 microns, or from 200 to 900 microns.

The binder may be any binder that withstands the heat cycles that occur during use of the aerosol-generating device, e.g., repeated heating at temperatures up to 300° C. As used herein, the “heat cycles” in an aerosol-generating device may be 14 “puffs” or draws on the device, or the use of the device for 6 minutes (whichever occurs first). In one embodiment, the binder exhibits virtually no flow at its melting temperature. This means a material, that when heated to its melting temperature, exhibits little to no polymer flow. Little to no polymer flow is advantageous because even at temperatures greater than the melting point of the binder, the binder will not be significantly repositioned or moved within the aerosol-generating device. Materials meeting these criteria include, but are not limited to, ultrahigh molecular weight polyethylene, very high molecular weight polyethylene, high molecular weight polyethylene, and combinations thereof. The binder is configured to undergo repeated heat cycles without structural deformation at 350° C. or less. For example, the structure of the binder undergoes less than a 10% change in pressure during repeated heat cycles. The binder may also be hydrophobic which enables water vapor condensation to facilitate heat removal and, advantageously, some selective filtration of phenols.

In some embodiments, the binder has a melt flow index (MFI, ASTM D1238 2013) of less than or equal to 3.5 g/10 min at 190° C. and 15 Kg (or 0-3.5 g/10 min at 190° C. and 15 Kg). In some embodiments, the binder has a melt flow index (MFI) of less than or equal to 2.0 g/10 min at 190° C. and 15 Kg (or 0-2.0 g/10 min at 190° C. and 15 Kg). One example of such a material is ultra high molecular weight polyethylene, UHMWPE, which has no polymer flow, MFI of approximately 0 g/10 min at 190° C. and 15 Kg, or an MFI of 0 to 1.0 g/10 min at 190° C. and 15 Kg. Another material may be very high molecular weight polyethylene, UHMWPE, which may have MFIs in the range of, for example, 1.0 to 2.0 g/10 min at 190° C. and 15 Kg. Yet another material is high molecular weight polyethylene, UHMWPE, which may have MFIs of, for example, 2.0 to 3.5 g/10 min at 190° C. and 15 Kg. For example, the porous mass may comprise a binder and active particles, wherein the binder is a very high molecular weight polyethylene and the active particles are activated carbon. The binder is configured to undergo repeated heat cycles without structural deformation.

In terms of molecular weight, “ultra-high molecular weight polyethylene” as used herein refers to polyethylene compositions with weight-average molecular weight of at least about 3×10⁶ g/mol. In some embodiments, the molecular weight of the ultra-high molecular weight polyethylene composition is between about 3×10⁶ g/mol and about 30×10⁶ g/mol, or between about 3×10⁶ g/mol and about 20×10⁶ g/mol, or between about 3×10⁶ g/mol and about 10×10⁶ g/mol, or between about 3×10⁶ g/mol and about 6×10⁶ g/mol. “Very-high molecular weight polyethylene” refers to polyethylene compositions with a weight average molecular weight of less than 3×10⁶ g/mol and greater than 1×10⁶ g/mol. In some embodiments, the molecular weight of the very-high molecular weight polyethylene composition is between 2×10⁶ g/mol and 3×10⁶ g/mol. “High molecular weight polyethylene” refers to polyethylene compositions with weight-average molecular weight of at least 3×10⁵ g/mol and may range 3×10⁵ g/mol to 1×10⁶ g/mol. For purposes of the present specification, the molecular weights referenced herein are determined in accordance with the Margolies equation (“Margolies molecular weight”).

Suitable polyethylene materials are commercially available from several sources including GUR® UHMWPE from Ticona Polymers LLC, a division of Celanese Corporation of Dallas, Tex., and DSM (Netherland), Braskem (Brazil), Beijing Factory No. 2 (BAAF), Shanghai Chemical, and Qilu (People's Republic of China), Mitsui and Asahi (Japan). Specifically, GUR polymers may include: GUR 2000 series (2105, 2122, 2122-5, 2126), GUR 4000 series (4120, 4130, 4150, 4170, 4012, 4122-5, 4022-6, 4050-3/4150-3), GUR 8000 series (8110, 8020), and GUR X series (X127, X143, X184, X168, X172, X192).

One example of a suitable polyethylene material is that having an intrinsic viscosity in the range from 5 dl/g to 30 dl/g and a degree of crystallinity of 80% or more as described in US Patent Application Publication No. 2008/0090081. Another example of a suitable polyethylene material is that having a molecular weight in the range from 300,000 g/mol to 2,000,000 g/mol as determined by ASTM-D 4020 (2011), an average particle size, D₅₀, from 300 and 1500 μm, and a bulk density from 0.25 to 0.5 g/ml as described in WO 2011/140053.

In one embodiment, the binder is a combination of various binders. In one embodiment, the binder has a particle size in the range from 0.5 to 5000 microns, e.g., from 10 to 1000 microns, from 20 to 600 microns, from 125 to 5000 microns, from 125 to 1000 microns, from 150 to 600 microns, from 200 to 600 microns, from 250 to 600 microns, or from 300 to 600 microns. In another embodiment, the binder may be a mixture of various particle sizes. In another embodiment, the binder may be a mixture of various particle sizes with an average particle size in the range from 125 to 5000 microns, e.g., from 125 to 1000 microns or from 125 to 600 microns.

Additionally, the binder may have a bulk density in the range from 0.10 to 0.55 g/cm³, e.g., from 0.17 to 0.50 g/cm³ or from 0.20 to 0.47 g/cm³.

In addition to the foregoing binder, other conventional thermoplastics may be used as the binder. Such thermoplastics may include, for example: polyolefins, polyesters, polyamides (or nylons), polyacrylics, polystyrenes, polyvinyls, and cellulosics. Polyolefins include, but are not limited to, polyethylene, polypropylene, polybutylene, polymethylpentene, copolymers thereof, mixtures thereof, and the like.

Polyethylenes further include low density polyethylene, linear low density polyethylene, high density polyethylene, copolymers thereof, mixtures thereof, and the like. Polyesters include polyethylene terephthalate, polybutylene terphthalate, polycyclohexylene dimethylene terphthalate, polytrimethylene terephthalate, copolymers thereof, mixtures thereof, and the like. Polyacrylics include, but are not limited to, polymethyl methacrylate, copolymers thereof, modifications thereof, and the like. Polystrenes include, but are not limited to, polystyrene, acrylonitrile-butadiene-styrene, styrene-acrylonitrile, styrene-butadiene, styrene-maleic anhydride, copolymers thereof, mixtures thereof, and the like. Polyvinyls include, but are not limited to, ethylene vinyl acetate, ethylene vinyl alcohol, polyvinyl chloride, copolymers thereof mixtures thereof and the like. Cellulosics include, but are not limited to, cellulose acetate, cellulose acetate butyrate, cellulose propionate, ethyl cellulose, copolymers thereof, mixtures thereof and the like.

The binder may assume any shape. Such shapes include spherical, hyperion, asteroidal, chrondular or interplanetary dust-like, cranulated, potato, irregular, or combinations thereof.

The porous mass is preferably effective at the removal of components from the tobacco smoke. A porous mass can be used to reduce the delivery of certain tobacco smoke components targeted by the World Health Organization (WHO) or certain compounds categorized by the Food and Drug Administration (FDA) as HPHCs (Harmful or Potentially Harmful compounds). For example, a porous mass comprising a binder and active particles, such as activated carbon, reduces the delivery of certain tobacco smoke or aerosol components to levels below the WHO recommendations.

The porous mass may be made by any means. In one embodiment, the active particles and binder are blended together and introduced into a mold. The mold is heated to a temperature above the melting point of the binder, e.g., in one embodiment about 200° C. and held at the temperature for a period of time (in one embodiment 40±10 minutes). Thereafter, the mass is removed from the mold and cooled to room temperature. In one embodiment, this process is characterized as a free sintering process, because the binder does not flow (or flows very little) at its melting temperature and no pressure is applied to the blended materials in the mold. In this embodiment, point bonds are formed between the active particles and the binder. This enables superior bonding and maximizes the interstitial space, while minimizing the blinding of the surface of the active particles by free flowing molten binder. Also see, U.S. Pat. Nos. 6,770,736, 7,049,382, 7,160,453, incorporated herein by reference.

Alternatively, one could make the porous mass using a process of sintering under pressure. As the mixture of the active particles and the binder are heated (or at a temperature which may be below, at, or above the melting temperature of the binder) a pressure is exerted on the mixture to facilitate coalescence of the porous mass.

Also, the porous mass may be made by an extrusion sintering process where the mixture is heated in an extruder barrel and extruded in to the porous mass.

The present invention will be better understood in view of the following non-limiting examples.

EXAMPLE 1

An aerosol-generating device was constructed using a porous mass for the aerosol-cooling element and/or support element compared to an aerosol-generating device with no aerosol-cooling element. The aerosol-generating devices were tested with a Cerulean SM450 smoking machine using the December 1999 Health Canada protocol for “Determination of Tar, Nicotine, and Carbon Monoxide in Mainstream Tobacco Smoke.” The maximum puff temperature was measured over 11 puffs using a thermocouple thermometer inserted into the mouthpiece. The porous mass in Samples A-C consisted of ultra-high molecular weight polyethylene and adsorbent carbon. The porous mass was attached to an aerosol-generating substrate with the support element in Samples A and B and without the support element in Sample C. In Samples B and C, the porous mass was placed immediately after the substrate and in Sample A, the porous mass was placed after the support element. The samples with a porous mass (A-C) were compared to a device with no cooling element (Sample D). The maximum puff temperatures for each construction are shown in Table 1 below.

TABLE 1 Maximum Temperature Sample Construction (° C.) A support element, porous mass, mouthpiece 57.8 B porous mass, support element, mouthpiece 59.0 C porous mass, mouthpiece 57.7 D support element, mouthpiece 63.0

As shown in Table 1, Sample D, which did not include a porous mass, had a greater maximum puff temperature than Samples A and B, which included the same components as Sample D but with the addition of a porous mass. Sample D also had a greater maximum puff temperature than Sample C, which included a porous mass and mouthpiece but did not include a support element. Accordingly, inclusion of a porous mass resulted in a reduction in maximum puff temperature and even allowed for the support element to be omitted in Sample D.

EXAMPLE 2

A porous mass was produced using the components shown below in Table 2. The encapsulated pressure drop of the porous mass was measured using a Cerulean Quantum Solo V benchtop pressure drop tester. The results are shown below in Table 2.

TABLE 2 Encapsulated Pressure Drop (mm water/ Sample Porous Mass mm length) 4 60% ultra high molecular weight polyethylene, 0.82 40% carbon 5 100% ultra high molecular weight polyethylene 1.27 6 100% plasticized cellulose acetate plastic 0.18

As shown in Table 2, the encapsulated pressure drop was decreased from Sample 5 to 4 by adding 40% carbon. The encapsulated pressure drop of the porous mass containing plasticized cellulose acetate plastic was even less than that of Samples 4 and 5.

While the invention has been described in detail, modifications within the spirit and scope of the invention will be readily apparent to those of skill in the art. It should be understood that aspects of the invention and portions of various embodiments and various features recited above and/or in the appended claims may be combined or interchanged either in whole or in part. In the foregoing descriptions of the various embodiments, those embodiments which refer to another embodiment may be appropriately combined with other embodiments as will be appreciated by one of ordinary skill in the art. Furthermore, those of ordinary skill in the art will appreciate that the foregoing description is by way of example only, and is not intended to limit the invention. All US patents and publications cited herein are incorporated by reference in their entirety. 

We claim:
 1. An aerosol-generating device comprising: an aerosol-generating article, wherein the aerosol-generating article comprises: an aerosol-forming substrate; a support element; an aerosol-cooling element; and a mouthpiece, wherein at least one of the support element, the aerosol cooling element, and the mouthpiece comprises a porous mass comprising from 20 to 100 wt. % binder and from 0 to 80 wt. % active or inactive particles.
 2. The device of claim 1, wherein the support element comprises the porous mass.
 3. The device of claim 1, wherein the aerosol-cooling element comprises the porous mass.
 4. The device of claim 1, wherein the mouthpiece comprises the porous mass.
 5. The device of claim 1, wherein the support element and the aerosol-cooling element comprise the porous mass.
 6. The device of claim 1, wherein the support element and the mouthpiece comprise the porous mass.
 7. The device of claim 1, wherein the aerosol cooling element and the mouthpiece comprise the porous mass.
 8. The device of claim 1, wherein the support element, the aerosol cooling element, and the mouthpiece comprise the porous mass.
 9. The device of claim 1, wherein the binder comprises a very high molecular weight polyethylene, an ultra high molecular weight polyethylene, or combinations thereof.
 10. The device of claim 1, wherein the binder is selected from the group consisting of polyolefins, polyesters, polyamides, polyacrylics, polystrenes, polyvinyls, cellulosics, and combinations thereof.
 11. The device of claim 9, wherein the binder further comprises polyolefins, polyesters, polyamides, polyacrylics, polystrenes, polyvinyls, cellulosics, or combinations thereof.
 12. The device of claim 1, wherein the active particles are selected from the group consisting of ion exchange resins, desiccants, silicates, molecular sieves, silica gels, activated alumina, perlite, sepiolite, Fuller's Earth, magnesium silicate, metal oxides, activated carbon, activated charcoals, and combinations thereof.
 13. The device of claim 1, wherein the inactive particles comprise heat stable materials.
 14. The device of claim 1, wherein the inactive particles comprise adsorbent carbons selected from the group consisting of porous grade carbons, graphite, low activity carbons, and non-activated carbons.
 15. The device of claim 1, wherein the inactive particles comprise inorganic solids selected from the group consisting of ceramics, glass, alumina, vermiculite, clays, bentonite, and inert materials.
 16. The device of claim 1, wherein the porous mass has an encapsulated pressure drop of less than 3.0 mm water/mm length.
 17. The device of claim 1, wherein the binder is configured to undergo repeated heat cycles without structural deformation.
 18. The device of claim 17, wherein the binder is configured to undergo less than a 10% change in pressure drop.
 19. The device of claim 1, wherein the porous mass is configured to provide a multi-path air flow.
 20. The device of claim 1, wherein the support and the aerosol-cooling element are combined into a single unit and wherein the pressure drop is substantially the same as compared to the support and aerosol-cooling elements as separate units. 